Drag scraper for dredging silt

ABSTRACT

The invention includes a scraper and its combination with a catamaran. The scraper has a top wall, side and rear walls, an open front and bottom, a blade adjacent to the rear wall and an outwardly extending support shoe secured to each side wall adjacent and parallel to but spaced from its bottom edge. The top and side walls are reinforced by flanges at the front end where hooks are secured for a chain to pull the scraper forwardly. Water escape openings are provided in top and side walls. The catamaran comprises two spaced floats and lifting mechanism so that the scraper used in combination therewith can be lifted into the space between the floats and lowered into contact with the silt at the bottom of a body of water.

[ 51 July 25, 1972 [54] DRAG SCRAPER FOR DREDGING SILT [72] Inventor:Henry Albert Loy, 87 N. 11th West,

Provo, Utah 84601 [22] Filed: July 15, 1970 [21] Appl.No.: 54,910

52 us. Cl ..l72/26.5, 37/71,;7/115 511 .1502: 3/60 [58] Field of Search..172/26.5, 26.6; 37/1 15, 135, 37/71 [56] References Cited UNITEDSTATES PATENTS 1,498,162 6/1924 Gillespie ..37/1l5 X 1,777,626 10/1930Rayburn ..37/135 1,453,540 5/1923 Beach et al.. .172/26.6 X 1,395,98811/1921 Sherwoodm. ..37/135 2,812,596 11/1957 Schofield ..l72/26.5

46,463 2/1865 Gore ..37/71 X 1,266,153 5/1918 Pratt ..172/26.5 1,721,4797/1929 Beaumont. .....172/26.5

142,988 9/1873 Brobston ..37/71 8,840 3/1852 Hamilton ..37/7l X FOREIGNPATENTS OR APPLICATIONS 242,962 4/ 1960 Australia ..37/71 659,433 l/1964ltaly ..37/1 35 7,036 4/1927 Australia ..172/26.5

Primary Examiner-Robert E. Pulfrey Assistant Examiner-Clifford D.Crowder Attorney-George H. Mortimer 57] ABSTRACT The invention includesa scraper and its combination with a catamaran. The scraper has a topwall, side and rear walls, an open front and bottom, a blade adjacent tothe rear wall and an outwardly extending support shoe secured to eachside wall adjacent and parallel to but spaced from its bottom edge. Thetop and side walls are reinforced by flanges at the front end wherehooks are secured for a chain to pull the scraper forwardly. Waterescape openings are provided in top and side walls. The catamarancomprises two spaced floats and lifting mechanism so that the scraperused in combination therewith can be lifted into the space between thefloats and lowered into contact with the silt at the bottom of a body ofwater.

10 Claims, 6 Drawing Figures Patented July 25, 1972 3,679,004

2 Sheets-Sheet l Patented July 25, 1972 2 Sheets-Sheet 2 FIG. 2

DRAG SCRAPER FOR DREDGING SILT BACKGROUND OF THE INVENTION Lakes are fedby rivers and streams carrying silt insuspension that settles out in therelatively quiescent conditions prevailing there. This silt builds up onthe bottom of the lake and, over a period of years, raises the level ofthe water, assuming approximately constant volume of water in the lake,and floods land adjacent to the shore. A somewhat similar build up ofsilt takes place in portions of the beds of therivers flowing into andfrom the lake where the rate of flow of the water is slow compared tothe rate where silt is picked up. The problem ofsilt build up in thebeds of lakes and rivers has long been recognized and many devices andmethods have been proposed for dredging the beds of rivers and lakes.Many of these devices are complex pieces of equipment that are expensiveto manufacture and use.

SUMMARY OF THE INVENTION The present invention includes apparatus fordredging silt from lake and river bottoms.

The apparatus comprises a simple and relatively inexpensive scraper andcatamaran for moving the scraper to a position remote from the shore sothat it can be pulled in to the shore to deposit the load of silt bymerely lifting the scraper above the load. The scraper can also be usedto agitate deposited silt a considerable distance from shore toresuspend it in the water that has currents normally moving shorewardwhere the silt will settle again and can be removed to the shore byrelatively short travel of the scraper.

BRIEF DESCRIPTION OF THE APPARATUS FIG. I is an isometric view of thescraper from above the right rear corner;

FIG. 2 is a side view of the right side of the scraper;

FIG. 3 is an isometric view of the interior of the scraper from belowlooking into it from the front;

FIG. 3(a) is a fragmentary detail of a portion of a scraper pullingmeans;

FIG. 4 is an isometric view of the catamaran with scraper in raisedposition; and

FIG. 5 is an isometric view of a toothed blade that may be removablysecured to the scraper to loosen compacted silt.

the

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The apparatusfor dredging silt comprises a scraper I and a catamaran 5.

The scraper I comprises a top wall of rectangular shape, preferablyapproximately square and while ,not restricted to any particular sizeand gauge a convenient and practical size is about 6 feet by 6 feet by54; inch thick. Secured to the top wall I0 are side walls 12 and a rearwall 14. These walls may be integral, with the top wall i.e., part ofthe same steel plate, or they may be separate pieces of steel plate ofsimilar gauge suitably welded together along their contacting edges. Theside walls may have any suitable width, e.g., about 24 to 26 inches, antthe same length as the top wall. The rear wall 14 may be narrower thanthe side walls, e.g., about 14 to 16 inches wide and the same length asthe width of the top wall. There is no front or bottom wall, thusleaving the front and bottom open, as may best be seen in FIG. 3.

Secured to the rear wall 14 is a scraper blade 16 that is slopeddownwardly and forwardly at any suitable angle, e.g., at an angle ofabout 36 to the top wall 10. It preferably has the same length as therear wall 14 so that it may be secured at its ends, to the side walls 12as well as along its upper edge to the rear wall 14, e.g., by welding.The blade 16 may have any suitable width but it is preferred to make itwide enough to extend a short distance below the plane of the bottomedges of the side walls 12, as may be seen in FIGS. 2 and 3, and a widthof about 18 inches is satisfactory for this purpose.

The front ends of the top and side walls are preferably reinforced byspaced flanges I8 and 20 made from similar steel plate which aresuitably secured, preferably by welding, to these walls along theircontacting-areas.

Preferably the side walls I2 have secured thereto, e.g., by weldingalong the contacting areas, an outwardly extending shoe 22 whichdesirably is about the same length and gauge as the side wall. The shoes22 should be secured to their respective side walls adjacent to butspaced from the bottom edges thereof, e.g., some 5 or 6 inches from thebottom edges, and they may have any desired width that will serve toprevent the scraper from sinking too deeply into loose silt it is toremove by scraping along the bottom of a body of water. A width of about5 inches has been found to be suitable for the shoes of a scraper of thedimensions and weight described above. The

w front ends of the shoes 22 are preferably secured-to the flanges 18and 20 which desirably terminate at the shoes at their lower ends asseen in FIGS. 1, 2 and 3. The lower front corner of each side wall ispreferably cut off at an angle below the shoe 22 to form a sloping frontend 24. The lower rear corner of each side wall is also preferably cutoff to form a sloping rear end 26 to which the ends of the scraper blade16 may be secured, e.g., by welding.

As the scraper is dragged forwardly along the bottom of the body ofwater being dredged it is desirable to provide water escape openings orholes to facilitate filling the body of the scraper full of silt. Suchopenings may be provided in the rearward port of the scraper, e.g., inthe top wall as shown at 28 and in the upper part of the rear wall 14 asshown at 30. i.e.. adjacent to the juncture of the top and rear walls.

Means are provided for pulling the scraper in a forward directionincluding U-shaped hooks 32, 34, 36 and 38 inserted into holes drilledin the flange 18 with their ends welded to flange 20 as shown in FIGS.1', 2 and 3. A chain 40 of suitable length is provided which has itsends secured by hooks 32 and 38 to the scraper adjacent to the bottomends of the flanges I8 and 20. These hooks are passed through an endlink in the chain 40 before they are secured as described to theflanges.

The chain 40 then runs up the flange 18 to. hooks 34 and 36 which secureit at these intermediate points to the upper end of the flanges, againby passing through a link that is large enough to receive the hook aswell as the other two links which are secured to it. The bight orconnecting part of the chain 40 is long enough to form a V on top of thescraper I when laid on it, as seen in FIG. I, with the apex at about thecenter of the top wall 10.

At the rear end of each shoe 22 a U-shaped hook 42 (only one shown inthe drawing) is suitably secured, e.g., by welding, with the end linkofa chain 43 held within the bight of the hook which extends beyond theend of the shoe 22, as seen in fig. I. This chain is somewhat longerthan the distance between the hooks 42 and may serve a number offunctions including a drag to stir up silt to suspend it, a pull chainto draw the scraper backwards, a lift chain for the back end of thescraper, used either along or together with the front chain 40 so as togive the scraper any desired angle of inclination relative to thehorizontal, and the like.

Near the center of its rear wall 14 and at its upper edge, a U- shapedhook 44 may be provided which is suitably secured with the bight thereofabove the surface of the top wall 10. To the top wall 10 approximatelymidway between the side walls and somewhat forward of the center ofgravity an eye plate 45 may be suitably secured, e.g., by welding. In apreferred embodiment having a top wall about 6 feet square, the eyeplate 45 may be centered some 28 inches from the back and 44 inches fromthe front which is still somewhat in front of the center of gravity sothat is the scraper is lifted by the eye plate the front end will besomewhat higher than the back end, as seen in FIG. 4. These means makeit possible to lift the scraper in a number of ways, e.g., by an upwardlifting force on 45 alone, or an upward lifting force on both 44 and 45,or an upward lifting force on chain 40, chain 43 or both 40 and 43. Hook44 may also serve to hold chain 43 up while the scraper is being moved,if this position is desired.

Additional means for moving the scraper forward with the pulling forceat the proper height for varying conditions of the deposit on the lakeor river bed includes a bar 46 having a hook 47 at each end and a chain48 connected at its ends to said hoods which may be removably connectedto selected links of chain 40 between the hooks 32 and 34 and 36 and 38,respectively, as may be seen in FIG. 3 and 3a.

Referring now to FIG. 4, the catamaran comprises two floats 50 which maybe elongated hollow cylinders with tapered ends made of any suitablematerial and of sufficient length and diameter that they displace avolume of water equivalent in weight to the weight of the scraper andcatamaran without sinking too deeply into the water. The floats 50 arespaced apart a distance larger than the width of the scraper by a frame52 which comprises comprises side bars 54 running along the floats adistance greater than the length of the scraper l to which they aresecured by any suitable means, e.g., bands 55, and cross bars 56 at thefront and rear ends of the side bars to which they are suitably secured,e.g., by welding. Spacing bars 57 may also be provided between bands 55to which they are secured at their ends. Between the ends of the sidebars 54 are uprights 58, the lower ends of which may be secured, e.g.,by welding, to the side bars. A top bar 60 is suitably secured to theupper ends of the upright bars 58. Braces 62 are secured to the uprights58 and the side bars 54 to hold the uprights and side bars inapproximately right angular relation to the uprights 58. A winch 66 ismounted on the top bar 60 which comprises a rotable reed 68 mounted nearthe center of the top bar and a drive means 70 for the reel which may beof any suitable kind, e.g., an electric motor, a crank or the like. Awire rope 72 or the like has one end wound on the reel 68 and the otherend may be secured to the scraper, e.g., to eye plate 45.

When the scraper l is lifted solely by the eye plate 45, and the plateis located somewhat forward of the center of gravity as described above,the scraper tilts to somewhat of an angle as seen in FIG. 4. Ifit isdesired to give the scraper a horizontal position when it is lifted, alifting force can be applied also to hook 46, either by a separate wirerope and reel or by suitably connecting a single lifting rope to bothpositions, as those skilled in this art will readily understand.Similarly a lifting force may be applied to the centers of chains 40 and43, if desired.

In some lake and river beds the deposits ofsilt become compacted so thata plain scraper blade such as 16 does not readily loosen and scoop it upwhen the scraper is pulled forwardly. In such cases it is preferred tosecure to the lower edge thereof a toothed blade such as shown in FIG. 5which comprises a steel bar 80, e.g., inch X 5 inches X 6 feet having aplurality of teeth 82 welded thereto which may be made of suitablesteel, e.g., /2 X 2 X inches, preferably with a sharpened front edge 84.The toothed blade 80 may be secured to the lower edge of the scraperblade 16 in any suitable manner, e.g., by a plurality of bolts passingthrough openings 86 in the bar 80 and aligned openings in the scraperblade 16.

The method of dredging silt from the bottom of a body of water, e.g., alake or river, comprises placing the scraper of the invention asdescribed above on the bottom of the body of water with the front endpointed in the direction of the shore. The distance of the scraper fromthe shore may be varied and depends on the circumstances and theequipment being worked with. For example, if one is dredging near toshore the scraper may be used with a crane that has vertical andhorizontal movement generating means. In such case, the crane puts thescraper as far from shore as desired using the horizontal and verticalmovement generating means. Then the scraper is dragged along the bottomtoward the shore by using the horizontal movement generating meansattached to the chain 40 or 48 as circumstances require. When thescraper is on the shore at the place where its load of silt is to bedeposited, the scraper is moved backward and/or upward away from itsload of silt, e.g., the vertical movement generating means may lift thescraper to deposit through the open bottom thereof the lead of silt ithas brought up with it from the bed of the body water as it was draggedalong it. If one is dredging from a considerable distance from theshore, the catamaran 5 is used to take the scraper to the site to bedredged, the winch 66 is operated to lower the scraper to the bottom ofthe body of water, the catamaran is then moved, either by power suppliedfrom an outboard motor secured to the frame 52 or by a power boat aheadof the catamaran which tows it toward the shore and simultaneously pullsthe scraper. When the catamaran is close to the shore the winch isoperated to lift it from its load of silt which can then be brought ontoshore as described above.

It has been discovered that silt at points distant from the shore of alake can be moved largely be natural currents in the water to the shoreby agitating the silt away from the shore to resuspend it in the water.The natural currents then move the suspended silt toward the shore andredeposit it there where it can be pulled up on the shore in the mannerdescribed above. In using the scraper l for this purpose it is towedalong the bottom of the lake in the area that is to be deepened by apower boat connected to the chain 40 or 48. Even though the scraperfills up with silt, it still is able to loosen other silt and agitate itto suspend it in the water near the point of agitation. The normalcurrents of the lake that move toward the shore bring the suspended siltto the shore where much of it redeposits near enough to be removed bycrane operation of the scraper as described.

Another way of operating the scraper 1 involves use of the catamaran 5and a winch or Windlass anchored on the shore. The catamaran carries thescraper to the place remote from shore that is to be dredged with a wirerope or chain of the windlass on shore attached to the chain 40 48 andlowers the scraper to the bottom with the front aimed at the shore. TheWindlass on shore then reels in the chain or rope pulling the scraperand catamaran to the shore. When the floats 50 hit the shore the reel 79plays out its rope to permit the scraper to be pulled up on the shore bythe shore Windlass. Then the winch 66 operates to wind up the rope onthe reel 68, pulling the scraper loose from its load of silt which isthus deposited at the desired location and bringing the scraper back tothe catamaran which then lifts it clear to return to the place to bedredged.

Although the invention has been described and illustrated in connectionwith certain specific apparatus and methods, modifications andvariations can be made as those skilled in the art will appreciatewithout departing from the principles of the invention set forthhereinabove.

lclaim:

1. Apparatus for dredging silt which comprises a scraper having arectangular top wall, side and rear walls, each side wall being of thesame length to said top wall and having parallel top and bottom edges, adownwardly and forwardly sloping scraper blade secured therein adjacentto said rear wall, the bottom and front of said scraper being open, anoutwardly extending support shoe secured to each side wall adjacent andparallel to but spaced from its bottom edge, and means for pulling saidscraper in a forward direction.

2. Apparatus as set forth in claim 1 in which said top wall has waterescape openings adjacent to said rear wall.

3. Apparatus as set forth in claim 1 in which said rear wall has waterescape openings adjacent to said top wall.

4. Apparatus as set forth in claim 1 in which said side walls haveoutwardly extending support shoes of the same length as said side walls.

5. Apparatus as set forth in claim 4 in which said side walls havebackwardly sloping front ends below said shoes.

6. Apparatus as set forth in claim 1 in which said top and side wallsare reinforced at their front ends by outwardly extending flanges abovesaid shoes.

7. Apparatus as set forth in claim 6 in which said flanges include twoadjacent but spaced bars secured to said walls and shoes along theircontacting areas and extend outwardly at right angles.

8. Apparatus as set forth in claim I in which the rear wall is narrowerthan said side walls, the scraper blade is secured to the lower edge ofsaid rear wall and to the adjacent side walls and slopes forwardly anddownwardly at an angle of about 36 with respect to the top wall.

9. Apparatus as set forth in claim 6 in which said means for pulling thescraper forward includes forwardly extending hooks secured in saidflanges and a chain secured to said hooks.

10. Apparatus for dredging silt which comprises a catamaran having twospaced floats, a frame supported on said floats having side bars, twospaced cross bars, a braced upright secured to each side bar and atopbar connecting the tops of said uprights. a scraper having a rectangulartop wall, side and rear walls, each side wall being of the same lengthas said top wall and having parallel top and bottom edges, a downwardlyand forwardly sloping scraper blade secured therein adjacent to saidrear wall, the bottom and front of said scraper being open, andoutwardly extending support shoe secured to each side wall adjacent andparallel to but spaced from its bottom edge, and means on said top barfor lifting said scraper into the space between the floats and crossbars and lowering it into contact with silt.

1. Apparatus for dredging silt which comprises a scraper having arectangular top wall, side and rear walls, each side wall being of thesame length to said top wall and having parallel top and bottom edges, adownwardly and forwardly sloping scraper blade secured therein adjacentto said rear wall, the bottom and front of said scraper being open, anoutwardly extending support shoe secured to each side wall adjacent andparallel to but spaced from its bottom edge, and means for pulling saidscraper in a forward direction.
 2. Apparatus as set forth in claim 1 inwhich said top wall has water escape openings adjacent to said rearwall.
 3. Apparatus as set forth in claim 1 in which said rear wall haswater escape openings adjacent to said top wall.
 4. Apparatus as setforth in claim 1 in which said side walls have outwardly extendingsupport shoes of the same length as said side walls.
 5. Apparatus as setforth in claim 4 in which said side walls have backwardly sloping frontends below said shoes.
 6. Apparatus as set forth in claim 1 in whichsaid top and side walls are reinforced at their front ends by outwardlyextending flanges above said shoes.
 7. Apparatus as set forth in claim 6in which said flanges include two adjacent but spaced bars secured tosaid walls and shoes along their contacting areas and extend outwardlyat right angles.
 8. Apparatus as set forth in claim 1 in which the rearwall is narrower than said side walls, the scraper blade is secured tothe lower edge of said rear wall and to the adjacent side walls andslopes forwardly and downwardly at an angle of about 36* with respect tothe top wall.
 9. Apparatus as set forth in claim 6 in which said meansfor pulling the scraper forward includes forwardly extending hookssecured in said flanges and a chain secured to said hooks.
 10. Apparatusfor dredging silt which comprises a catamaran having two spaced floats,a frame supported on said floats having side bars, two spaced crossbars, a braced upright secured to each side bar and a top bar connectingthe tops of said uprights, a scraper having a rectangular top wall, sideand rear walls, each side wall being of the same length as said top walland having parallel top and bottom edges, a downwardly and forwardlysloping scraper blade secured therein adjacent to said rear wall, thebottom and front of said scraper being open, and outwardly extendingsupport shoe secured to each side wall adjacent and parallel to butspaced from its bottom edge, and means on said top bar for lifting saidscraper into the space between the floats and cross bars and lowering itinto contact with silt.